Proportional Flow Control and Counterbalance Valve Having Single Seat Configuration

ABSTRACT

An example valve includes: a first port configured to be fluidly coupled to an actuator; a second port configured to be fluidly coupled to a reservoir; a third port configured to provide an output pilot fluid signal and receive an input pilot fluid signal; a fourth port configured to be fluidly coupled to a source of fluid; a pilot poppet configured to be subjected to a first fluid force of fluid received at the first port and configured to be subjected to a second fluid force of the input pilot fluid signal; a solenoid actuator sleeve that is axially movable between an unactuated state and an actuated state; and at least one setting spring configured to apply a biasing force on the pilot poppet.

BACKGROUND

A meter-in valve can be configured to control fluid flow to an actuatorin a hydraulic system in such a manner that there is a restriction inthe amount of fluid flowing to the actuator. The meter-in valve can beactuated electrically, mechanically, pneumatically, hydraulically, ormanually.

Counterbalance valves are hydraulic valves configured to hold andcontrol negative or gravitational loads. They may be configured tooperate, for example, in applications that involve the control ofsuspended loads, such as mechanical joints, lifting applications,extensible movable bridge, winches, etc.

In some applications, the counterbalance valve, which may also bereferred to as an overcenter valve, can be used as a safety device thatprevents an actuator from moving if a failure occurs (e.g., a hoseburst) or could be used as a load-holding valve (e.g., on a boomcylinder of a mobile machinery). The counterbalance valve allowscavitation-free load lowering, preventing the actuator from overrunningwhen pulled by the load (gravitational load).

An actuator that has two chambers can have one or more meter-in valvesto control fluid flow to the chambers and counterbalance valves thatcontrol fluid flow out of the chambers. Additional valves (e.g., checkvalves) are typically added to perform additional functionalities in ahydraulic system.

Such a hydraulic system can involve many hydraulic connections betweenthe different valves. Also, the valves can be placed in a manifold thatincludes complex fluid passages and ports to connect the various valvesin the hydraulic system. It may thus be desirable to have a valve thatreduces complexity and cost of the hydraulic system.

SUMMARY

The present disclosure describes implementations that relate to aproportional flow control and counterbalance valve having single seatconfiguration.

In a first example implementation, the present disclosure describes avalve. The valve includes: (i) a plurality of ports comprising: (a) afirst port configured to be fluidly coupled to a hydraulic actuator, (b)a second port configured to be fluidly coupled to a reservoir, (c) athird port configured to provide an output pilot fluid signal andreceive an input pilot fluid signal, and (d) a fourth port configured tobe fluidly coupled to a source of fluid; (ii) a pilot poppet configuredto be subjected to: (a) a first fluid force of fluid received at thefirst port acting on the pilot poppet in a proximal direction, and (b) asecond fluid force of the input pilot fluid signal acting on the pilotpoppet in the proximal direction; (iii) a solenoid actuator sleeve thatis axially movable between an unactuated state and an actuated state;and (iv) at least one setting spring configured to apply a biasing forceon the pilot poppet in a distal direction to seat the pilot poppet at apilot poppet seat. The valve is configured to operate in at least twomodes of operation: (i) a counterbalance valve mode of operation inwhich the first fluid force and the second fluid force cooperate toovercome the biasing force of the at least one setting spring, therebyunseating the pilot poppet and fluidly coupling the first port to thesecond port, and (ii) a proportional flow control mode of operation inwhich the solenoid actuator sleeve moves to the actuated state, therebyallowing the fourth port to be fluidly coupled to: (a) the first port toprovide fluid flow thereto, and (b) the third port to provide the outputpilot fluid signal to be communicated externally.

In a second example implementation, the present disclosure describes ahydraulic system including a source of fluid; a reservoir; an actuatorhaving a first chamber and a second chamber therein; a counterbalancevalve comprising: (i) a load port fluidly coupled to the second chamberof the actuator, and (ii) a pilot port, wherein the counterbalance valveis configured to allow fluid flow from the load port to the reservoirwhen a pilot fluid signal is received at the pilot port; and a valve.The valve comprises: a first port fluidly coupled to the first chamberof the actuator, a second port fluidly coupled to the reservoir, a thirdport configured to provide an output pilot fluid signal to the pilotport of the counterbalance valve and receive an input pilot fluidsignal, and a fourth port fluidly coupled to the source of fluid. Thevalve further comprises: (i) a pilot poppet configured to be subjectedto: (a) a first fluid force of fluid received at the first port actingon the pilot poppet in a proximal direction, and (b) a second fluidforce of the input pilot fluid signal acting on the pilot poppet in theproximal direction; (ii) a solenoid actuator sleeve that is axiallymovable between an unactuated state and an actuated state; and (iii) atleast one setting spring configured to apply a biasing force on thepilot poppet in a distal direction to seat the pilot poppet at a pilotpoppet seat. The valve is configured to operate in at least two modes ofoperation: (i) a counterbalance valve mode of operation in which thefirst fluid force and the second fluid force cooperate to overcome thebiasing force of the at least one setting spring, thereby unseating thepilot poppet and fluidly coupling the first port to the second port, and(ii) a proportional flow control mode of operation in which the solenoidactuator sleeve moves to the actuated state, thereby allowing the fourthport to be fluidly coupled to: (a) the first port to provide fluid flowto the first chamber of the actuator, and (b) the third port to providethe output pilot fluid signal to be communicated to the pilot port ofthe counterbalance valve to actuate the counterbalance valve and allowfluid to flow from the second chamber to the reservoir.

In a third example implementation, the present disclosure describes avalve. The valve includes: (i) a plurality of ports comprising: a firstport configured to be fluidly coupled to a hydraulic actuator, a secondport configured to be fluidly coupled to a reservoir, a third portconfigured to provide an output pilot fluid signal and receive an inputpilot fluid signal, and a fourth port configured to be fluidly coupledto a source of fluid; (ii) a pilot poppet comprising a distal poppetportion having a first diameter and a proximal poppet portion having asecond diameter smaller than the first diameter; (iii) a solenoidactuator sleeve that is axially movable between an unactuated state andan actuated state; and (iv) at least one setting spring configured toapply a biasing force on the pilot poppet in a distal direction to seatthe pilot poppet at a pilot poppet seat having a pilot poppet seatdiameter. The pilot poppet is configured to be subjected to: (i) a firstfluid force of fluid received at the first port, wherein the firstdiameter, the second diameter, and pilot poppet seat diameter areconfigured such that the first fluid force is substantially zero, and(ii) a second fluid force of the input pilot fluid signal acting on thepilot poppet in a proximal direction. The valve is configured to operatein at least two modes of operation: (i) a counterbalance valve mode ofoperation in which the second fluid force overcomes the biasing force ofthe at least one setting spring, thereby unseating the pilot poppet andfluidly coupling the first port to the second port, and (ii) aproportional flow control mode of operation in which the solenoidactuator sleeve moves to the actuated state, thereby allowing the fourthport to be fluidly coupled to: (a) the first port to provide fluid flowthereto, and (b) the third port to provide the output pilot fluid signalto be communicated externally.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects,implementations, and features described above, further aspects,implementations, and features will become apparent by reference to thefigures and the following detailed description.

BRIEF DESCRIPTION OF THE FIGURES

The novel features believed characteristic of the illustrative examplesare set forth in the appended claims. The illustrative examples,however, as well as a preferred mode of use, further objectives anddescriptions thereof, will best be understood by reference to thefollowing detailed description of an illustrative example of the presentdisclosure when read in conjunction with the accompanying Figures.

FIG. 1 illustrates a cross-sectional side view of a valve, in accordancewith an example implementation.

FIG. 2 illustrates cross-sectional side view of a solenoid tube, inaccordance with an example implementation.

FIG. 3 illustrates a three-dimensional partial perspective view showingan armature coupled to a solenoid actuator sleeve, in accordance withanother example implementation.

FIG. 4 illustrates a partial cross-sectional side view of acounterbalance valve portion of a valve, in accordance with an exampleimplementation.

FIG. 5 illustrates a cross-sectional side view of a valve operating as ameter-in valve controlling fluid flow from a fourth port to a firstport, in accordance with an example implementation.

FIG. 6 illustrates a hydraulic system, in accordance with an exampleimplementation.

FIG. 7 is a flowchart of a method for operating a valve, in accordancewith an example implementation.

DETAILED DESCRIPTION

In examples, a pilot-operated counterbalance valve can be used on thereturn side of a hydraulic actuator for lowering a large negative loadin a controlled manner. The counterbalance valve generates a preload orback-pressure in the return line that acts against the main drivepressure so as to maintain a positive load, which therefore remainscontrollable. Particularly, if a speed of the actuator increases,pressure on one side of the actuator may drop and the counterbalancevalve may then act to restrict the flow to controllably lower the load.

An example pilot-operated counterbalance valve can have three ports: aport fluidly coupled to a first side of the actuator (e.g., rod side ofa hydraulic actuator cylinder), a second port operating as an outletport that is fluidly coupled to a tank or reservoir, and a third portthat can be referred to as a pilot port. The pilot port can be fluidlycoupled via a pilot line to a supply line connected to a second side ofthe actuator (e.g., head side of the hydraulic actuator cylinder).

The counterbalance valve can have a spring that acts against a movableelement (e.g., a spool or a poppet), and the force of the springdetermines a pressure setting of the counterbalance valve. The pressuresetting is the pressure level of fluid at the first port of thecounterbalance valve that can cause the counterbalance valve to open.

The back-pressure in the first side of the actuator cooperates with apilot signal provided via the pilot line to open the counterbalancevalve. The counterbalance valve can be characterized by a ratio betweena first surface area on which the pilot signal acts and a second surfacearea on which the pressure induced in the first side of the actuatoracts within the counterbalance valve. Such ratio may be referred to as“pilot ratio.”

The pilot signal effectively reduces the pressure setting of thecounterbalance valve. The extent of reduction in the pressure setting isdetermined by the pilot ratio. For example, if the pilot ratio is 3 to 1(3:1), then for each 10 bar increase in pressure level of the pilotsignal, the pressure setting of the setting spring is reduced by 30 bar.As another example, if the pilot ratio is 8 to 1 (8:1), then for each 10bar increase in the pressure level of pilot signal, the pressure settingof the setting spring is reduced by 80 bar.

At the same time, each side of the hydraulic actuator can be fluidlycoupled to a flow control valve, i.e., meter-in valve, which controlsfluid flow to the associated side of the hydraulic actuator. Thus, eachside of the hydraulic actuator, i.e., the head side and the rod side, isfluidly coupled to a meter-in valve that controls fluid flow thereto anda counterbalance valve that controls fluid flow therefrom. In someexamples, additional valves, e.g., check valves, can also be used toperform additional functionalities in the hydraulic system.

Conventional configurations can involve separate meter-in valve andcounterbalance valve for each side and a manifold in which all thevalves are disposed. Having at least four valves connected in a manifoldcan increase size, cost, and complexity of the manifold. Also,conventional systems involve the fluid flow exiting the counterbalancevalve going through the meter-in valve before flowing to the reservoir.This configuration can lead to trapped fluid having high pressure in thehydraulic line connecting the counterbalance valve to the meter-invalve. To relieve such trapped fluid, a more complex ventedcounterbalance valve is often used.

Therefore, it may be desirable to have a valve that integrates meter-invalve operations along with counterbalance valve operations. This way,two valves rather than four separate valves can be used to operate thehydraulic actuator, thereby reducing complexity, cost, and size of themanifold. It may further be desirable to have the valve configured toperform the meter-in and counterbalance operations with a single seatrather than two seats, to reduce cost.

Also, it may be desirable that such valve provides direct fluid path forflow exiting the counterbalance valve portion of the disclosed valve tothe reservoir. This way, no pressurized fluid is trapped as inconventional system. Further, in some applications, it may be desirableto have a counterbalance valve that is insensitive to pressure levelfluctuations at the load port. The disclosed valve can be configured tobe load-insensitive if desired.

FIG. 1 illustrates a cross-sectional side view of a valve 100, inaccordance with an example implementation. The valve 100 may be insertedor screwed into a manifold having ports corresponding to ports of thevalve 100 described below, and can thus fluidly coupled the valve 100 toother components of a hydraulic system.

The valve 100 includes a counterbalance valve portion 102 and aproportional flow control or meter-in valve portion 104. The valve 100includes a housing 106 having a longitudinal cylindrical cavity therein.The longitudinal cylindrical cavity of the housing 106 is configured tohouse parts of the counterbalance valve portion 102 and the meter-invalve portion 104.

The valve 100 includes a main sleeve 108 received at a distal end of thehousing 106. The valve 100 includes a first port 110 at a nose or distalend of the main sleeve 108. The first port 110 can also be referred toas a load port and is configured to be fluidly coupled to a chamber of ahydraulic actuator.

The valve 100 also includes a second port 112. The second port 112 canbe referred to as a tank or reservoir port and can be configured to befluidly coupled to a tank or reservoir of hydraulic fluid to providereturn flow from the hydraulic actuator to the reservoir. The reservoircan have fluid at a low pressure level, e.g., 0-70 pounds per squareinch (psi). The second port 112 can include a set of return flowcross-holes, such as return flow cross-hole 113, disposed in the mainsleeve 108.

The valve 100 also includes a third port 114. The third port 114 can bereferred to as a pilot fluid signal port. The third port 114 can includea set of cross-holes that can be referred to as pilot signalcross-holes, disposed in the housing 106. Particularly, the third port114 can include a first pilot signal cross-hole 115A and a second pilotsignal cross-hole 115B. The first pilot signal cross-hole 115A isconfigured to receive an input pilot fluid signal to actuate thecounterbalance valve portion 102 of the valve 100. Further, the valve100 is configured such that, when the meter-in valve portion 104 isactuated, an output pilot fluid signal is communicated to the secondpilot signal cross-hole 115B so as to provide or communicate the outputpilot fluid signal externally to a pilot port of a counterbalance valveon the other side of the actuator.

The valve 100 can further include a fourth port 116. The fourth port 116can be referred to as an inlet port and is configured to be coupled to asource of fluid (e.g., a pump, an accumulator, etc.) capable ofproviding fluid at high pressures (e.g., 1000-5000 psi). The fourth port116 can include a set of cross-holes that can be referred to as inletflow cross-holes, such as inlet flow cross-hole 117, disposed in aradial array about the housing 106.

The valve 100 also includes a second sleeve 118 disposed within thehousing 106 longitudinally adjacent to the main sleeve 108. The secondsleeve 118 includes a respective set of cross-holes, such as cross-holes119A, 119B, disposed in a radial array about the second sleeve 118. Thecross-holes 119A, 119B of the second sleeve 118 are respectively fluidlycoupled to the inlet flow cross-hole 117.

The main sleeve 108 includes a respective longitudinal cylindricalcavity therein. The valve 100 includes a main flow piston 120 that isdisposed, and slidably accommodated, in the longitudinal cylindricalcavity of the main sleeve 108. The term “piston” is used herein toencompass any type of movable element, such as a spool-type movableelement or a poppet-type movable element.

Further, the term “slidably accommodated” is used throughout herein toindicate that a first component (e.g., the main flow piston 120) ispositioned relative to a second component (e.g., the main sleeve 108)with sufficient clearance therebetween, enabling movement of the firstcomponent relative to the second component in the proximal and distaldirections. As such, the first component (e.g., main flow piston 120) isnot stationary, locked, or fixedly disposed in the valve 100, butrather, is allowed to move relative to the second component (e.g., themain sleeve 108).

A main chamber 122 is formed within the main sleeve 108, and the mainflow piston 120 is hollow such that interior space of the main flowpiston 120 is comprised in the main chamber 122. The main chamber 122 isfluidly coupled to the first port 110. The valve 100 includes aring-shaped member 123 fixedly disposed, at least partially, within themain sleeve 108 at a distal end thereof. The valve 100 also includes amain flow check spring 124 disposed about an exterior peripheral surfaceof the main flow piston 120.

The ring-shaped member 123 protrudes radially inward within the cavityof the main sleeve 108 to form a support for a distal end of the mainflow check spring 124. A proximal end of the main flow check spring 124acts against a shoulder 125 projecting radially outward from the mainflow piston 120. With this configuration, the distal end of the mainflow check spring 124 is fixed, whereas the proximal end of the mainflow check spring 124 is movable and interfaces with the main flowpiston 120. Thus, the main flow check spring 124 is configured to biasthe main flow piston 120 in a proximal direction (e.g., to the left inFIG. 1) toward the main sleeve 108.

In the position shown in FIG. 1, a proximal end of the main flow piston120 interfaces with an interior distal surface of the main sleeve 108 toform a metal-to-metal contact 126 between the main flow piston 120 andthe main sleeve 108. With this configuration, the main flow piston 120and the main flow check spring 124 operate as a check valve configuredto block fluid flow from the first port 110 to the fourth port 116 whenthe meter-in valve portion 104 is unactuated, while allowing fluid flowfrom the fourth port 116 to the first port 110 when the meter-in valveportion 104 is actuated as described below with respect to FIG. 5. Theterm “block” is used throughout herein to indicate substantiallypreventing fluid flow except for minimal or leakage flow of drops perminute, for example.

The valve 100 includes a pilot poppet 128 slidably accommodated withinthe main sleeve 108. When the counterbalance valve portion 102 isunactuated (i.e., when the valve 100 precludes fluid flow from the firstport 110 to the second port 112), the pilot poppet 128 is configured tobe seated at a pilot poppet seat 130 formed by an interior surface ofthe main flow piston 120.

As described in detail below with respect to FIG. 4, the counterbalancevalve portion 102 is configured to be actuated when pressure level atthe first port 110 and/or the pressure level of the pilot signalreceived at the third port 114 are sufficient to unseat the pilot poppet128 off the pilot poppet seat 130. The valve 100 is shown in FIG. 1 withthe pilot poppet 128 being seated, thereby blocking a fluid path fromthe first port 110 to the second port 112.

As depicted in FIG. 1, the pilot poppet 128 has a proximal poppetportion 131 that has a smaller diameter than a respective diameter ofthe distal poppet portion of the pilot poppet 128. The proximal poppetportion 131 of the pilot poppet 128 is guided within a first spacer 132and a second spacer 134 that are both slidably accommodated within themain sleeve 108.

Further, the valve 100 further includes a wire ring 136 formed in anannular groove disposed in an exterior peripheral surface of theproximal poppet portion 131 of the pilot poppet 128. The wire ring 136engages with an interior surface of the second spacer 134. With thisconfiguration, a force that is applied to the second spacer 134 in theproximal direction is transferred to the pilot poppet 128 via the wirering 136.

The valve 100, particularly the meter-in valve portion 104, includes asolenoid tube 138 configured as a cylindrical housing or body disposedwithin and received at a proximal end of the housing 106, such that thesolenoid tube 138 is coaxial with the housing 106. A solenoid coil 140can be disposed about an exterior surface of the solenoid tube 138. Thesolenoid coil 140 is retained between a proximal end of the housing 106and a coil nut 142 having internal threads that can engage a threadedregion formed on the exterior peripheral surface of the solenoid tube138 at its proximal end.

FIG. 2 illustrates a cross-sectional side view of the solenoid tube 138,in accordance with an example implementation. As depicted, the solenoidtube 138 has a cylindrical body 200 having therein a first chamber 202within a distal side of the cylindrical body 200 and a second chamber204 within a proximal side of the cylindrical body 200. The solenoidtube 138 includes a pole piece 203 formed as a protrusion within thecylindrical body 200. The pole piece 203 separates the first chamber 202from the second chamber 204. In other words, the pole piece 203 dividesa hollow interior of the cylindrical body 200 into the first chamber 202and the second chamber 204. The pole piece 203 can be composed ofmaterial of high magnetic permeability.

Further, the pole piece 203 defines a channel 205 therethrough. In otherwords, an interior peripheral surface of the solenoid tube 138 at orthrough the pole piece 203 forms the channel 205, which fluidly couplesthe first chamber 202 to the second chamber 204. As such, pressurizedfluid provided to the first chamber 202 is communicated through thechannel 205 to the second chamber 204.

In examples, the channel 205 can be configured to receive a pintherethrough so as to transfer linear motion of one component in thesecond chamber 204 to another component in the first chamber 202 andvice versa, as described below. As such, the channel 205 can includechamfered circumferential surfaces at its ends (e.g., an end leadinginto the first chamber 202 and another end leading into the secondchamber 204) to facilitate insertion of such a pin therethrough.

The solenoid tube 138 has a distal end 206, which is configured to becoupled to the housing 106, and a proximal end 208. Particularly, thesolenoid tube 138 can have a first threaded region 210 disposed on anexterior peripheral surface of the cylindrical body 200 at the distalend 206 that is configured to threadedly engage with correspondingthreads formed in the interior peripheral surface of the housing 106.

Also, the solenoid tube 138 can have a second threaded region 212disposed on the exterior peripheral surface of the cylindrical body 200at the proximal end 208 and configured to be threadedly engaged withcorresponding threads formed in the interior peripheral surface of thecoil nut 142. Further, the solenoid tube 138 can have a third threadedregion 214 disposed on an interior peripheral surface of the cylindricalbody 200 at the proximal end 208 and configured to threadedly engagewith corresponding threads formed in a component of a manual adjustmentactuator 168 as described below (see FIG. 1). The solenoid tube 138 canalso have one or more shoulders formed in the interior peripheralsurface of the cylindrical body 200 that can mate with respectiveshoulders of the manual adjustment actuator 168 to enable alignment ofthe manual adjustment actuator 168 within the solenoid tube 138.

Referring back to FIG. 1, the solenoid tube 138 is configured to housean armature 144 in the first chamber 202. The armature 144 is slidablyaccommodated within the solenoid tube 138 (i.e., the armature 144 canmove axially within the solenoid tube 138).

The valve 100 further includes a solenoid actuator sleeve 146 disposedpartially within a distal end of the solenoid tube 138. The armature 144is mechanically coupled to, or linked with, the solenoid actuator sleeve146. As such, if the armature 144 moves axially (e.g., in the proximaldirection), the solenoid actuator sleeve 146 moves along with thearmature 144 in the same direction. The solenoid actuator sleeve 146 isdisposed through a guide piece 147.

The armature 144 can be coupled to the solenoid actuator sleeve 146 inseveral ways. FIG. 3 illustrates a three-dimensional partial perspectiveview showing the armature 144 coupled to the solenoid actuator sleeve146, in accordance with an example implementation. As shown, the guidepiece 147 comprises two slots 300, 301 through which members 302, 304 ofthe solenoid actuator sleeve 146 extend to be coupled to the armature144.

Particularly, the members 302, 304 have male T-shaped ends such as maleT-shaped end 306 of the member 302, and the armature 144 can have acorresponding female T-slot 308 formed as an annular internal grooveconfigured to receive the male T-shaped end 306. The term “T-shaped” isused herein to indicate a structure having two members that meetperpendicularly. With this configuration, the armature 144 and thesolenoid actuator sleeve 146 are coupled to each other, such that if thearmature 144 moves, the solenoid actuator sleeve 146 moves therewith.

Referring back to FIG. 1, the guide piece 147 rests or is securedagainst a shoulder 145 formed in the interior surface of the housing106. The valve 100 further includes a main spring 148 disposed between aring-shaped spacer 149 and the guide piece 147. The ring-shaped spacer149 is disposed at a proximal end of the second sleeve 118 and isconfigured to interact with a protrusion on an exterior peripheralsurface of the solenoid actuator sleeve 146. With this configuration,the main spring 148 applies a respective biasing force against thesolenoid actuator sleeve 146 in the distal direction. When the armature144 and the solenoid actuator sleeve 146 move in the proximal direction(e.g., to the left in FIG. 1), the solenoid actuator sleeve 146compresses the main spring 148 and moves against its biasing force.

The armature 144 includes a longitudinal channel 150 formed therein. Thearmature 144 further includes a protrusion 151 within the longitudinalchannel 150 that can be configured to guide linear motion of componentssuch as spring cap 162 and pin 166 described below.

As mentioned above, the solenoid tube 138 includes the pole piece 203formed as a protrusion within the cylindrical body 200. The pole piece203 is separated from the armature 144 by the airgap 152. The valve 100further includes an armature spring 153 that applies a biasing force onthe armature 144 in the distal direction that can ensure axial contactbetween components of the valve 100 when the valve 100 is orientedvertically, for example.

The solenoid actuator sleeve 146 forms therein a chamber 154 configuredto house one or more setting springs. In the example implementationshown in FIG. 1, the valve 100 includes a nested spring configurationcomprising a first setting spring 156 and a second setting springs 158disposed in the chamber 154 within the solenoid actuator sleeve 146.

The setting springs 156, 158 are disposed between a distal or firstspring cap 160 and a proximal or second spring cap 162. As such,respective distal ends of the setting springs 156, 158 contact the firstspring cap 160, whereas respective proximal ends of the setting springs156, 158 contact the second spring cap 160.

The first spring cap 160 can also be referred to as a pilot spring capas it interfaces with the proximal poppet portion 131 of the pilotpoppet 128. As depicted in FIG. 1, the first spring cap 160 receives ata distal tip thereof a ball 163 that contacts a proximal end of theproximal poppet portion 131. As such, the setting springs 156, 158 applya biasing force on the pilot poppet 128 toward the pilot poppet seat 130via the first spring cap 160 and the ball 163.

With the configuration of the valve 100 shown in FIG. 1, the firstsetting spring 156 and the second setting spring 158 are disposed inparallel with respect to the first spring cap 160 and the pilot poppet128. Particularly, any fluid force applied to the pilot poppet 128 isthe sum of the forces applied respectively to the setting springs 156,158, and the amount of strain (deformation) or axial motion of the pilotpoppet 128 is the same as the strains of the individual setting springs156, 158.

As such, the combination of the first setting spring 156 and the secondsetting spring 158 has an equivalent or effective spring rate k_(eq)that is the summation of the respective spring rates of the settingsprings 156, 158. Particularly, the effective spring rate k_(eq) can bedetermined as k₁+k₂, where k₁ is the spring rate of the setting spring156, and the k₂ is the spring rate of the setting spring 158. It shouldbe noted, however, that in other example implementations, one settingspring can be used.

The effective spring rate k_(eq) determines a magnitude of a biasingforce applied on the pilot poppet 128 in the distal direction by way ofthe combined action of the setting springs 156, 158. In other words, thefirst setting spring 156 and the second setting spring 158 cooperate toapply a biasing force on the pilot poppet 128 in the distal direction.Such biasing force determines the pressure setting of the valve 100,where the pressure setting is the pressure level of fluid at the firstport 110 at which the valve 100 can open to provide fluid from the firstport 110 to the second port 112.

Specifically, based on the equivalent spring rate k_(eq) of the settingsprings 156, 158 and their respective lengths, the setting springs 156,158 exert a particular preload or biasing force on the first spring cap160 and the pilot poppet 128 in the distal direction, thus causing thepilot poppet 128 to be seated at the pilot poppet seat 130 of the mainflow piston 120. The biasing force of the setting springs 156, 158determines the pressure setting of the counterbalance valve portion 102of the valve 100 as described below.

FIG. 4 illustrates a partial cross-sectional side view of thecounterbalance valve portion 102 of the valve 100, in accordance with anexample implementation. As mentioned above, pressurized fluid receivedat the first port 110 is communicated through the main chamber 122 tothe pilot poppet 128. The pressurized fluid thus applies a force in theproximal direction (e.g., to the left in FIG. 4) on an area of the pilotpoppet 128 that is equal to the circular area of the pilot poppet seat130. Assuming that the pilot poppet seat diameter of the pilot poppetseat 130 is D_(PS) as labelled in FIG. 4, the area of the pilot poppetseat 130 is

${A_{PS} = {\pi \frac{D_{PS}^{2}}{4}}}.$

Further, as depicted in FIG. 4, the pilot poppet 128 has a longitudinalchannel 400 and an orifice 402 that communicate fluid received at thefirst port 110 to an annular surface area A_(annular) at the back end ofthe distal poppet portion of the pilot poppet 128 as labelled in FIG. 4.

Assuming the distal poppet portion of the pilot poppet 128 has a largediameter of D_(L 1) and the proximal poppet portion 131 has a smalldiameter D_(S) as labelled in FIG. 4, the pressurized fluid communicatedthrough the longitudinal channel 400 and the orifice 402 applies a forceon the pilot poppet 128 on the annular surface area

${A_{annular} = {\pi \frac{\left( {D_{L}^{2} - D_{S}^{2}} \right)}{4}}}.$

With this configuration, the pressurized fluid at the first port 110 canapply a net force

F_(PP) on the pilot poppet 128 in the proximal direction (e.g., to theleft in FIG. 4). The net force F_(PP) on the pilot poppet 128 is equalto pressure level P₁ of fluid at the first port 110 multiplied bydifferential relief area.

${A_{DR} = {\frac{\pi}{4}\left( {D_{S}^{2} + D_{PS}^{2} - D_{L}^{2}} \right)}}.$

As such:

$\begin{matrix}{F_{PP} = {{P_{1}A_{DR}} = {{P_{1} \cdot \frac{\pi}{4}}\left( {D_{S}^{2} + D_{PS}^{2} - D_{L}^{2}} \right)}}} & (1)\end{matrix}$

The pressure setting of the valve 100 can be determined by dividing thebiasing force that the setting springs 156, 158 applies to the pilotpoppet 128 (via the first spring cap 160) by the differential reliefarea A_(DR).

The net force F_(PP) might not be sufficiently large to overcome thepressure setting of the valve 100 (e.g., overcome the biasing force ofthe setting springs 156, 158 on the pilot poppet 128) if pressure levelof fluid at the first port 110 is not sufficiently high. The net forceis, however, supplemented by a force applied to the pilot poppet 128 bythe pilot pressure fluid signal received at the third port 114.

The pilot pressure fluid signal received at the third port 114 iscommunicated through the first pilot signal cross-hole 115A and achannel or cross-hole 404 formed in the main sleeve 108) to a chamberwithin the main sleeve 108 that houses the first spacer 132 and thesecond spacer 134. The pilot pressure fluid signal applies a force onthe first spacer 132 and the second spacer 134 in the proximaldirection. This force is transferred to the pilot poppet 128 via thewire ring 136. Further, the pilot pressure fluid signal also flows fromthe first pilot signal cross-hole 115A, through an orifice 401 disposedin the main sleeve 108, then through a longitudinal channel 403 disposedin the main sleeve 108, and through an orifice 405 disposed in the mainsleeve 108 to the second port 112, which can be fluidly coupled to areservoir. Also, the valve 100 includes a check ball 406 that blocksfluid received at the second pilot signal cross-hole 115B.

As depicted in FIG. 4, the valve 100 can include an O-ring 408 disposedbetween back-up rings 410, 412 disposed about an exterior peripheralsurface of the proximal poppet portion 131 of the pilot poppet 128. Ifthe pilot pressure fluid signal has a pressure level that is higher thanpressure level at the first port 110, the pilot pressure fluid signalapplies a force on the back-up rings 410, 412 and the O-ring 408 in adistal direction. The back-up rings 410, 412 and the O-ring 408 may thenmove in the distal direction until they contact an enlarged diametersection of the distal poppet portion of the pilot poppet 128, therebyapplying a force on the pilot poppet 128 in the distal direction.

With this configuration, the net force that the pilot pressure fluidsignal received at the third port 114 applies on the pilot poppet 128can be determined by multiplying pressure level of the pilot pressurefluid signal by an area difference equal to

${{A_{1} - A_{2}} = {\pi\left( {\frac{D_{1}^{2}}{4} - \frac{D_{2}^{2}}{4}} \right)}},$

where D₁ is equal to a diameter of the second spacer 134 and A₁ is thearea of a surface having the diameter D₁ of the second spacer 134, andwhere D₂ is equal to a diameter of the back-up rings 410, 412 and A₂ isthe area of a surface having the diameter D₂ of either of the back-uprings 410, 412. D₁ and D₂ are labelled in FIG. 4. The area difference A₁minus A₂ can be referred to as effective or differential pilot areaA_(DP).

As depicted in FIG. 4, D₁ is larger than D₂. With this configuration,the pilot pressure fluid signal applies respective forces in oppositedirections on the pilot poppet 128. Because D₁ is larger than D₂, thepilot pressure fluid signal applies a net force on the pilot poppet 128in the proximal direction (e.g., to the left in FIGS. 4).

With the configuration of the valve 100, several forces are applied tothe pilot poppet 128. The setting springs 156, 158 apply a first forceon the pilot poppet 128 via the first spring cap 160 in the distaldirection. On the other hand, the pressurized fluid at the first port110 can apply a second force on the pilot poppet 128 in the proximaldirection, and the pilot pressure fluid signal received at the thirdport 114 applies a third force on the pilot poppet 128 also in theproximal direction.

When the pressure levels of the pressurized fluid at the first port 110and the pilot pressure fluid signal at the third port 114 aresufficiently high to cause the second and third forces acting in theproximal direction to overcome the first force of the setting springs156, 158 acting in the distal direction, the pilot poppet 128 can bepushed or displaced axially in the proximal direction to be unseated offthe pilot poppet seat 130 formed in the main sleeve 108. As the pilotpoppet 128 moves axially in the proximal direction, the pilot poppet 128can push the first spring cap 160 in the proximal direction against thesetting springs 156, 158, thereby compressing the setting springs 156,158. As a result of compression of the setting springs 156, 158, thefirst force that the setting springs 156, 158 apply on the pilot poppet128 in the distal direction increases. Thus, the pilot poppet 128 canmove axially in the proximal direction until force equilibrium betweenthe second and third forces on one hand, and the increased first forceon the other hand is reached.

FIG. 4 illustrates the valve 100 with the pilot poppet 128 unseated offthe pilot poppet seat 130, thereby forming a flow area 414. As such, aflow path is formed and fluid at the first port 110 flows through themain chamber 122, the flow area 414, around the pilot poppet 128, thenthrough the return flow cross-hole 113, then to the second port 112,which can be fluidly coupled to the reservoir.

As mentioned above, a pilot ratio of a counterbalance valve determineshow the pressure setting of the counterbalance valve changes as thepilot pressure (i.e., the pressure level of the pilot pressure fluidsignal at the third port 114) changes. As an example, a 3:1 pilot ratioindicates that an increase of, for example, 10 bar in the pilot pressuredecreases the pressure setting by 30 bar. With the configuration of thevalve 100, the pilot ratio P_(R) can be determined as

${P_{R} = \frac{A_{DP}}{A_{DR}}}.$

Referring back to equation (1), in a first example implementation, thevalve 100 can be configured such that the diameter D_(PS) is equal tothe diameter D_(L). In this case, the force F_(PP) is a force acting inthe proximal direction on the pilot poppet 128 as described above and isequal to

$F_{PP} = {{P_{1}A_{DR}} = {{P_{1} \cdot \frac{\pi}{4}}\left( D_{S}^{2} \right)}}$

In some example applications, it may be desirable to have the valve 100configured to be load-insensitive such that the counterbalance valveportion 102 can operate in a consistent manner regardless of thepressure level P₁ of the fluid received at the first port 110. In theseexample applications, the valve 100 can be configured such that thepilot poppet 128 is pressure-balanced with respect to the pressure levelat the first port 110. In other words, the net force F_(PP) that thefluid at the first port 110 applies to on the pilot poppet 128 can berendered substantially equal to zero by selecting the diameters D_(S),D_(PS), and D₁, such that the sum(D_(S) ²+D_(PS) ²−D_(L) ²) is equal tosubstantially zero. The term “substantially” is used herein to indicatethat the sum (D_(S) ²+D_(PS) ²−D_(L) ²) is within a threshold value(e.g., 0.001) from zero.

As an example for illustration, if D_(S)=0.125 inches (in), D_(PS)=0.287in, and D_(L)=0.3125 in, then the sum (D_(S) ²+D_(PS) ²−D_(L) ²) iszero. In this example, the force F_(PP)=P₁A_(DR)=P₁.0=0. The pilotpoppet 128 is thus pressure-balanced with respect to P₁, and regardlessof the pressure level P₁, the force that the fluid at the first port 110applies on the pilot poppet 128 is substantially zero (e.g., within athreshold value such as 0.5 Newton from zero). Rather, the force that isapplied against the biasing force of the setting springs 156, 158 is theforce applied by the pilot pressure fluid signal received at the thirdport 114. As such, in this case, the valve 100 is substantiallyload-insensitive (insensitive to pressure fluctuations at the first port110).

Further, in some applications, it may be desirable to have a manualadjustment actuator coupled to the valve 100 so as to allow for manualmodification of the preload of the setting springs 156, 158, while thevalve 100 is installed in the hydraulic system without disassembling thevalve 100. Particularly, referring back to FIG. 1, the valve 100includes a pin 166 disposed in the longitudinal channel 150 of thearmature 144, and the pin 166 is in contact with the second spring cap162. With this configuration, axial movement of the pin 166 causes thesecond spring cap 162 to also move axially, thereby changing the lengthof the setting springs 156, 158 and modifying their preload.Modification of the preload of the setting springs 156, 158 causesmodification of the pressure setting of the valve 100.

FIG. 1 illustrates the valve 100 having a manual adjustment actuator168. The manual adjustment actuator 168 is configured to allow foradjusting a maximum pressure setting of the valve 100 withoutdisassembling the valve 100. The manual adjustment actuator 168 includesan adjustment piston 170 that interfaces with or contacts the pin 166,such that longitudinal or axial motion of the adjustment piston 170causes the pin 166 and the second spring cap 162 coupled thereto to moveaxially therewith. The adjustment piston 170 can be threadedly coupledto a nut 172 at threaded region 174. The nut 172 in turn is threadedlycoupled to the solenoid tube 138 at the threaded region 214. As such,the adjustment piston 170 is coupled to the solenoid tube 138 via thenut 172. Further, the adjustment piston 170 is threadedly coupled atthreaded region 176 to another nut 178.

The adjustment piston 170 is axially movable within the second chamber204 of the solenoid tube 138. For instance, the adjustment piston 170can include an adjustment screw 180, such that if the adjustment screw180 is rotated in a first rotational direction (e.g., clockwise) theadjustment piston 170 moves in the distal direction (e.g., to the rightin FIG. 1) by engaging more threads of the threaded regions 174, 176. Ifthe adjustment screw 180 is rotated in a second rotational direction(e.g., counter-clockwise) the adjustment piston 170 is allowed to movein the proximal direction (e.g., to the left in FIG. 1) by disengagingsome threads of the threaded regions 174, 176.

Axial motion of the adjustment piston 170 results in axial motion of thepin 166 and the second spring cap 162, which is in contact with theproximal ends of the setting springs 156, 158. Thus, axial motion of theadjustment piston 170 causes a change in the length of the settingsprings 156, 158.

If the adjustment piston 170 moves in the distal direction, the settingsprings 156, 158 are compressed, and the biasing force applied to thefirst spring cap 160 and the pilot poppet 128 increases, therebyincreasing the pressure setting of the valve 100. If the adjustmentpiston 170 moves in the proximal direction, the setting springs 156, 158are allowed to extend and relax, and the biasing force applied to thefirst spring cap 160 and the pilot poppet 128 decreases, therebydecreasing the pressure setting of the valve 100. With thisconfiguration, the pressure setting of the valve 100 can be adjusted viathe manual adjustment actuator 168 without disassembling the valve 100.

In addition to operating in a counterbalance valve mode of operation asdescribed above with respect to FIGS. 1 and 4, the valve 100 can alsooperate as a proportional fluid flow control or meter-in valve thatmeters fluid from the fourth port 116 to the first port 110.

FIG. 5 illustrates a cross-sectional side view of the valve 100operating as a meter-in valve controlling fluid flow from the fourthport 116 to the first port 110, in accordance with an exampleimplementation. When an electrical current is provided through thewindings of the solenoid coil 140, a magnetic field is generated. Thepole piece 203 directs the magnetic field through the airgap 152 towardthe armature 144, which is movable and is attracted toward the polepiece 203. In other words, when an electrical current is applied to thesolenoid coil 140, the generated magnetic field forms a north and southpole in the pole piece 203 and the armature 144, and therefore the polepiece 203 and the armature 144 are attracted to each other.

Because the pole piece 203 is fixed and the armature 144 is movable, thearmature 144 can traverse the airgap 152 toward the pole piece 203, andthe airgap 152 is reduced in size. As such, a solenoid force is appliedon the armature 144, where the solenoid force is a pulling force thattends to pull the armature 144 in the proximal direction (to the left inFIG. 5). The solenoid force is proportional to a magnitude of theelectrical command or signal (e.g., magnitude of electrical current orvoltage applied to the solenoid coil 140).

The solenoid force applied to the armature 144 is also applied to thesolenoid actuator sleeve 146, which is coupled to the armature 144 asdescribed above. As the armature 144 is pulled in the proximaldirection, the armature 144 causes the solenoid actuator sleeve 146coupled thereto to move in the proximal direction as well.

As a result of the motion of the solenoid actuator sleeve 146 in theproximal direction, the main spring 148 is compressed in the proximaldirection. Thus, the biasing force that the main spring 148 applies onthe solenoid actuator sleeve 146 increases. The armature 144 and thesolenoid actuator sleeve 146 can move in the proximal direction untilthe biasing force of the main spring 148 balances the solenoid force. Assuch, the axial position of the armature 144 and the solenoid actuatorsleeve 146 can be proportional to the command signal provided to thesolenoid coil 140.

As the solenoid actuator sleeve 146 starts to move past a distal edge ofthe cross-holes 119A, 119B of the second sleeve 118 as depicted in FIG.5, the cross-holes 119A, 119B become partially unblocked (e.g., at leasta portion of the cross-holes 119A, 119B is exposed). The partial openingof the cross-holes 119A, 119B (the extent of portion of the cross-holes119A, 119B that is exposed) can be referred to as a flow restriction500.

As a result, fluid received at the fourth port 116 (which can be fluidlycoupled to a source of fluid such as a pump) flows through the inletflow cross-hole 117, the cross-holes 119A, 119B, and the flowrestriction 500 to an annular chamber 502. Fluid can then flow from theannular chamber 502 through the longitudinal channel 403 disposed in themain sleeve 108. The longitudinal channel 403 is isolated from (e.g.,fluidly decoupled from and does not intersect with) the cross-hole 404.

Fluid provided through the longitudinal channel 403 then applies arespective fluid force on the main flow piston 120 in the distaldirection. The fluid force applied on the main flow piston 120 can pushthe main flow piston 120 in the distal direction (e.g., to the right inFIG. 5) against the main flow check spring 124, thereby separating themain flow piston 120 from the main sleeve 108 (i.e., the main flowpiston 120 no longer contacts the main sleeve 108 at the metal-to-metalcontact 126). As a result, a flow area 506 is formed and fluid can flowfrom the longitudinal channel 403 through the flow area 506. Notably,the pilot poppet 128 has a protrusion or flanged portion 510 configuredto interface with the interior peripheral surface of the main sleeve 108at an overlap region 512 to block fluid flow from the fourth port 116 tothe return flow cross-hole 113 and the second port 112.

As the main flow piston 120 moves in the distal direction, the pilotpoppet 128 does not move. Particularly, the pilot poppet 128 does notmove due to interaction with the second spacer 134 via the wire ring 136and the first spacer 132 being precluded from movement in the distaldirection by a protrusion in the interior surface of the main sleeve 108beyond a particular axial position as depicted in FIG. 5.

As a result of the main flow piston 120 moving in the distal direction,while the pilot poppet 128 is precluded from moving therewith, the mainflow piston 120 is unseated off the pilot poppet 128 at the pilot poppetseat 130 and a flow area 508 is formed. As such, fluid can flow from thelongitudinal channel 403 through the flow area 506 and the flow area508, through the main chamber 122 to the first port 110, which can befluidly coupled to a first chamber of a hydraulic actuator. Fluid flowfrom the fourth port 116 to the first port 110 can be referred to asmeter-in flow.

Fluid exiting from a second chamber of the hydraulic actuator isprovided to a counterbalance valve to allow the fluid exiting the secondchamber to flow to the reservoir. To actuate the counterbalance valve,the fluid in the annular chamber 502 of the valve 100 flows throughanother longitudinal channel 514 disposed in the main sleeve 108,pushing the check ball 406 and flowing to the second pilot signalcross-hole 115B and the third port 114. The third port 114 can befluidly coupled to a pilot port of the counterbalance valve to provide apilot signal thereto and actuate the counterbalance valve. In examples,the counterbalance valve can be another valve 100 disposed on the otherside of the hydraulic actuator and operating in the counterbalance valvemode described above with respect to FIG. 4.

Thus, the valve 100 can be used as both a meter-in valve and acounterbalance valve in various hydraulic systems. The valve 100performs the meter-in valve and counterbalance valve operations whilehaving a single seat (i.e., the pilot poppet seat 130) rather than twoseats.

FIG. 6 illustrates a hydraulic system 600, in accordance with an exampleimplementation. The hydraulic system 600 includes two valves 100A, 100Bthat each symbolically represents the valve 100. The valves 100A, 100Bhave the same components of the valve 100. Therefore, the components orelements of the valves 100A, 100B are designated with the same referencenumbers used for the valve 100 with an “A” or “B” suffix to correspondto the valves 100A, 100B respectively.

The hydraulic system 600 includes a source 602 of fluid. The source 602of fluid can, for example, be a pump configured to provide fluid to theports 116A, 116B of the valves 100A, 100B. Such pump can be a fixeddisplacement pump, a variable displacement pump, or a load-sensingvariable displacement pump, as examples. Additionally or alternatively,the source 602 of fluid can be an accumulator.

The hydraulic system 600 also includes a reservoir 604 of fluid that canstore fluid at a low pressure (e.g., 0-70 psi). The second ports 112A,112B of the valves 100A, 100B are respectively fluidly coupled to thereservoir 604. The source 602 of fluid can be configured to receivefluid from the reservoir 604, pressurize the fluid, then providepressurized fluid to the ports 116A, 116B of the valves 100A, 100B,respectively.

The valves 100A, 100B operate as meter-in valves and counterbalancevalves to control fluid flow to and from an actuator 606. The actuator606 includes a cylinder 608 and a piston 610 slidably accommodated inthe cylinder 608. The piston 610 includes a piston head 612 and a rod614 extending from the piston head 612 along a central longitudinal axisdirection of the cylinder 608. The rod 614 is coupled to a load 616 andthe piston head 612 divides the inside space of the cylinder 608 into afirst chamber 618 and a second chamber 620.

As shown in FIG. 6, the port 110A of the valve 100A is fluidly coupledto the second chamber 620 of the actuator 606, whereas the port 110B ofthe valve 100B is fluidly coupled to the first chamber 618 of theactuator 606.

The hydraulic system 600 can further include a controller 622. Thecontroller 622 can include one or more processors or microprocessors andmay include data storage (e.g., memory, transitory computer-readablemedium, non-transitory computer-readable medium, etc.). The data storagemay have stored thereon instructions that, when executed by the one ormore processors of the controller 622, cause the controller 622 toperform operations described herein. Signal lines to and from thecontroller 622 are depicted as dashed lines in FIG. 6.

The controller 622 can receive input or input information comprisingsensor information via signals from various sensors or input devices inthe hydraulic system 600, and in response provide electrical signals tovarious components of the hydraulic system 600. For example, thecontroller 622 can receive a command or an input (e.g., from a joystickof a machine) to move the piston 610 in a given direction at aparticular desired speed (e.g., to extend or retract the piston 610).The controller 622 can then provide a signal to the valve 100A or thevalve 100B to move the piston 610 in the commanded direction and at adesired commanded speed in a controlled manner.

For example, to extend the piston 610 (i.e., move the piston 610 upwardin FIG. 6), the controller 622 can send a command signal to the solenoidcoil 140B of the valve 100B to actuate it and operate it as a meter-invalve as described above with respect to FIG. 5. As a result, fluid isprovided from the source 602 to the port 116B of the valve 100B, meteredthrough the valve 100B, and then provided to the port 110B of the valve100B. Fluid then flows to the first chamber 618 of the actuator 606 toextend the piston 610. As the piston 610 extends, fluid is forced out ofthe second chamber 620 and is provided to the port 110A of the valve100A.

In addition to fluid being metered through the valve 100B as it flowsfrom the port 116B to the port 110B, a pilot fluid signal is providedfrom the port 116B to the port 114B. The port 114B of the valve 100B isfluidly coupled through a pilot line 624 to the port 114A of the valve100A.

The pilot fluid signal provided to the port 114A of the valve 100Acauses the valve 100A to operate as a counterbalance valve. In otherwords, the pilot fluid signal provided to the port 114A can actuate thecounterbalance valve portion 102A of the valve 100A as described abovewith respect to FIG. 4 to allow fluid provided to the port 110A from thesecond chamber 620 to flow to the port 112A, which is fluidly coupled tothe reservoir 604. As such, the piston 610 extends at a speed that isbased on the magnitude of the command signal provided to the solenoidcoil 140B.

To retract the piston 610 (i.e., move the piston 610 downward in FIG.6), the controller 622 can send a command signal to the solenoid coil140A of the valve 100A to actuate it and operate it as a meter-in valveas described above with respect to FIG. 5. As a result, fluid isprovided from the source 602 to the port 116A of the valve 100A, meteredthrough the valve 100A, and then provided to the port 110A of the valve100A. Fluid then flows to the second chamber 620 of the actuator 606 toretract the piston 610. As the piston 610 retracts, fluid is forced outof the first chamber 618 and is provided to the port 110B of the valve100B.

In addition to fluid being metered through the valve 100A as it flowsfrom the port 116A to the port 110A, a pilot fluid signal is providedfrom the port 116A to the port 114A. The port 114A of the valve 100A isfluidly coupled through the pilot line 624 to the port 114B of the valve100B.

The pilot fluid signal provided to the port 114B of the valve 100Bcauses the valve 100B to operate as a counterbalance valve. In otherwords, the pilot fluid signal provided to the port 114B can actuate thecounterbalance valve portion 102B of the valve 100B as described abovewith respect to FIG. 4 to allow fluid provided to the port 110B from thefirst chamber 618 to flow to the port 112B, which is fluidly coupled tothe reservoir 604. As such, the piston 610 retracts at a speed that isbased on the magnitude of the command signal provided to the solenoidcoil 140A.

In contrast to conventional configurations that involve a meter-in valvethat is separate from a counterbalance valve for each of the chambers618, 620 and a manifold in which all the valves are disposed, each ofthe valves 100A, 100B perform the operations of both a meter-in valveand a counterbalance valve. As such, only two valves are used in thehydraulic system 600 rather than three or four valves. Also, asmentioned above, the valves 100A, 100B each have a single seatconfiguration rather than a two seat configuration, and thereforemanufacturing cost of the valves can be reduced.

Further, functionality of the check valves represented by the main flowpistons 120A, 120B are integrated in the valves 100A, 100B, and noadditional check valves are needed to preclude fluid flow from the ports110A, 110B to the ports 116A, 116B, respectively. Therefore, size, cost,and complexity of a manifold housing the valves 100A, 100B can bereduced.

Further, the configuration of the valves 100A, 100B provide for a directpath from their respective counterbalance valve portions 102A, 102B tothe reservoir 604. Therefore, no pressurized fluid is trapped betweenthe counterbalance valve portions 102A, 102B and a directional valve asin conventional systems, and no expensive vented counterbalance valvesare needed in the hydraulic system 600. Further, if desired in someapplications, the valves 100A, 100B can be configured to beload-insensitive such that pressure level of fluid at the ports 110A,110B does not affect operation of the counterbalance valve portions102A, 102B.

FIG. 7 is a flowchart of a method 700 for operating a valve, inaccordance with an example implementation. The method 700 shown in FIG.7 presents an example of a method that can be used with the valve 100(e.g., the valves 100A, 100B) shown throughout the Figures, for example.The method 700 may include one or more operations, functions, or actionsas illustrated by one or more of blocks 702-708. Although the blocks areillustrated in a sequential order, these blocks may also be performed inparallel, and/or in a different order than those described herein. Also,the various blocks may be combined into fewer blocks, divided intoadditional blocks, and/or removed based upon the desired implementation.It should be understood that for this and other processes and methodsdisclosed herein, flowcharts show functionality and operation of onepossible implementation of present examples. Alternative implementationsare included within the scope of the examples of the present disclosurein which functions may be executed out of order from that shown ordiscussed, including substantially concurrent or in reverse order,depending on the functionality involved, as would be understood by thosereasonably skilled in the art.

At block 702, the method 700 includes receiving an electrical commandsignal (e.g., from the controller 622) energizing the solenoid coil 140of the valve 100, where the valve 100 has: (i) the first port 110fluidly coupled to a chamber (e.g., the second chamber 620) of anactuator (e.g., the actuator 606), (ii) the second port 112 fluidlycoupled to a reservoir (e.g., the reservoir 604), (iii) the third port114 fluidly coupled to a pilot port of a counterbalance valve, and (iv)the fourth port 116 fluidly coupled to a source of fluid (e.g., thesource 602).

At block 704, the method 700 includes, responsively, operating the valve100 as a meter-in valve that: (i) meters fluid received at the fourthport 116 and provides metered fluid to the first port 110 to be providedto the chamber of the actuator, and (ii) provides an output pilot fluidsignal to through the third port 114 of the valve 100 to the pilot portof the counterbalance valve.

At block 706, the method 700 includes receiving an input pilot fluidsignal at the third port 114 of the valve 100.

At block 708, the method 700 includes, responsively, operating the valve100 in a counterbalance valve mode of operation, wherein fluid receivedat the first port 110 from the chamber of the actuator flows through thevalve 100 to the second port 112 of the valve 100, which is fluidlycoupled to the reservoir.

The detailed description above describes various features and operationsof the disclosed systems with reference to the accompanying figures. Theillustrative implementations described herein are not meant to belimiting. Certain aspects of the disclosed systems can be arranged andcombined in a wide variety of different configurations, all of which arecontemplated herein.

Further, unless context suggests otherwise, the features illustrated ineach of the figures may be used in combination with one another. Thus,the figures should be generally viewed as component aspects of one ormore overall implementations, with the understanding that not allillustrated features are necessary for each implementation.

Additionally, any enumeration of elements, blocks, or steps in thisspecification or the claims is for purposes of clarity. Thus, suchenumeration should not be interpreted to require or imply that theseelements, blocks, or steps adhere to a particular arrangement or arecarried out in a particular order.

Further, devices or systems may be used or configured to performfunctions presented in the figures. In some instances, components of thedevices and/or systems may be configured to perform the functions suchthat the components are actually configured and structured (withhardware and/or software) to enable such performance. In other examples,components of the devices and/or systems may be arranged to be adaptedto, capable of, or suited for performing the functions, such as whenoperated in a specific manner.

By the term “substantially” or “about” it is meant that the recitedcharacteristic, parameter, or value need not be achieved exactly, butthat deviations or variations, including for example, tolerances,measurement error, measurement accuracy limitations and other factorsknown to skill in the art, may occur in amounts that do not preclude theeffect the characteristic was intended to provide

The arrangements described herein are for purposes of example only. Assuch, those skilled in the art will appreciate that other arrangementsand other elements (e.g., machines, interfaces, operations, orders, andgroupings of operations, etc.) can be used instead, and some elementsmay be omitted altogether according to the desired results. Further,many of the elements that are described are functional entities that maybe implemented as discrete or distributed components or in conjunctionwith other components, in any suitable combination and location.

While various aspects and implementations have been disclosed herein,other aspects and implementations will be apparent to those skilled inthe art. The various aspects and implementations disclosed herein arefor purposes of illustration and are not intended to be limiting, withthe true scope being indicated by the following claims, along with thefull scope of equivalents to which such claims are entitled. Also, theterminology used herein is for the purpose of describing particularimplementations only, and is not intended to be limiting.

What is claimed is:
 1. A valve comprising: a plurality of portscomprising: (i) a first port configured to be fluidly coupled to ahydraulic actuator, (ii) a second port configured to be fluidly coupledto a reservoir, (iii) a third port configured to provide an output pilotfluid signal and receive an input pilot fluid signal, and (iv) a fourthport configured to be fluidly coupled to a source of fluid; a pilotpoppet configured to be subjected to: (i) a first fluid force of fluidreceived at the first port acting on the pilot poppet in a proximaldirection, and (ii) a second fluid force of the input pilot fluid signalacting on the pilot poppet in the proximal direction; a solenoidactuator sleeve that is axially movable between an unactuated state andan actuated state; and at least one setting spring configured to apply abiasing force on the pilot poppet in a distal direction to seat thepilot poppet at a pilot poppet seat, wherein the valve is configured tooperate in at least two modes of operation: (i) a counterbalance valvemode of operation in which the first fluid force and the second fluidforce cooperate to overcome the biasing force of the at least onesetting spring, thereby unseating the pilot poppet and fluidly couplingthe first port to the second port, and (ii) a proportional flow controlmode of operation in which the solenoid actuator sleeve moves to theactuated state, thereby allowing the fourth port to be fluidly coupledto: (a) the first port to provide fluid flow thereto, and (b) the thirdport to provide the output pilot fluid signal to be communicatedexternally.
 2. The valve of claim 1, further comprising: a main sleevecomprising the first port and the second port; and a housing having acylindrical cavity in which the main sleeve is at least partiallydisposed, wherein the housing comprises the third port and the fourthport.
 3. The valve of claim 2, further comprising: a main flow pistonconfigured to be have a metal-to-metal contact with the main sleeve toblock fluid flow between the fourth port and the first port when thevalve operates in the counterbalance valve mode of operation, whereinthe main flow piston comprises the pilot poppet seat; and a main flowcheck spring configured to bias the main flow piston toward the mainsleeve, wherein when the valve operates in the proportional flow controlmode of operation, fluid flows from the fourth port through alongitudinal channel formed in the main sleeve and applies a respectivefluid force on the main flow piston against the main flow check spring,thereby separating the main flow piston from the main sleeve, andopening a fluid path from the fourth port to the first port.
 4. Thevalve of claim 1, wherein the solenoid actuator sleeve comprises achamber therein, wherein the at least one setting spring is disposed inthe chamber within the solenoid actuator sleeve.
 5. The valve of claim1, wherein the at least one setting spring comprises: (i) a firstsetting spring, and (ii) a second setting spring, wherein the firstsetting spring and the second setting spring are disposed in parallelwith respect to the pilot poppet in a nested spring configuration. 6.The valve of claim 5, further comprising: a first spring cap, whereinrespective distal ends of the first setting spring and second settingspring contact the first spring cap, such that the first setting springand second setting spring apply the biasing force on the pilot poppetvia the first spring cap; and a second spring cap, wherein respectiveproximal ends of the first and second setting springs contact the secondspring cap.
 7. The valve of claim 6, further comprising: a manualadjustment actuator having: (i) an adjustment piston, (ii) a pin havinga proximal end interfacing with the adjustment piston and a distal endinterfacing with the second spring cap, such that axial motion of theadjustment piston causes the pin and the second spring cap coupledthereto to move axially, thereby adjusting the biasing force of thefirst setting spring and second setting spring on the pilot poppet. 8.The valve of claim 1, further comprising: a solenoid coil; a pole piece;and an armature that is mechanically coupled to the solenoid actuatorsleeve, such that when the solenoid coil is energized, a solenoid forceis applied to the armature and the solenoid actuator sleeve coupledthereto, thereby (i) causing the armature and the solenoid actuatorsleeve to move axially in the proximal direction toward the pole piece,and (ii) placing in the solenoid actuator sleeve in the actuated state.9. The valve of claim 8, further comprising: a main spring configured tobias the solenoid actuator sleeve to the unactuated state, wherein thesolenoid force causes the solenoid actuator sleeve to move against arespective biasing force of the main spring until the respective biasingforce balances the solenoid force.
 10. The valve of claim 8, wherein thefourth port comprises one or more inlet flow cross-holes, wherein thesolenoid actuator sleeve is configured to (i) block the one or moreinlet flow cross-holes when the solenoid actuator sleeve is in theunactuated state, and (ii) allow the one or more inlet flow cross-holesto be fluidly coupled to the first port when the solenoid actuatorsleeve is in the actuated state.
 11. The valve of claim 8, furthercomprising: a solenoid tube comprising: (i) a cylindrical body, (ii) afirst chamber defined within the cylindrical body and configured toreceive the armature therein, and (iii) a second chamber defined withinthe cylindrical body, wherein the pole piece is formed as a protrusionwithin the cylindrical body, wherein the pole piece is disposed betweenthe first chamber and the second chamber, and wherein the pole piecedefines a respective channel therethrough, such that the respectivechannel of the pole piece fluidly couples the first chamber to thesecond chamber.
 12. The valve of claim 1, wherein the third portcomprises: (i) a first pilot signal cross-hole configured to receive theinput pilot fluid signal when the valve operates in the counterbalancevalve mode of operation, and (ii) a second pilot signal cross-holeconfigured to provide the output pilot fluid signal when the valveoperates in the proportional flow control mode of operation.
 13. Thevalve of claim 12, further comprising: a check ball configured to allowthe output pilot fluid signal to be communicated via the second pilotsignal cross-hole when the valve operates in the proportional flowcontrol mode of operation, while blocking the input pilot fluid signalat the second pilot signal cross-hole when the valve operates in thecounterbalance valve mode of operation.
 14. A hydraulic systemcomprising: a source of fluid; a reservoir; an actuator having a firstchamber and a second chamber therein; a counterbalance valve comprising:(i) a load port fluidly coupled to the second chamber of the actuator,and (ii) a pilot port, wherein the counterbalance valve is configured toallow fluid flow from the load port to the reservoir when a pilot fluidsignal is received at the pilot port; and a valve comprising: (i) afirst port fluidly coupled to the first chamber of the actuator, (ii) asecond port fluidly coupled to the reservoir, (iii) a third portconfigured to provide an output pilot fluid signal to the pilot port ofthe counterbalance valve and receive an input pilot fluid signal, and(iv) a fourth port fluidly coupled to the source of fluid, and whereinthe valve further comprises: a pilot poppet configured to be subjectedto: (i) a first fluid force of fluid received at the first port actingon the pilot poppet in a proximal direction, and (ii) a second fluidforce of the input pilot fluid signal acting on the pilot poppet in theproximal direction, a solenoid actuator sleeve that is axially movablebetween an unactuated state and an actuated state, and at least onesetting spring configured to apply a biasing force on the pilot poppetin a distal direction to seat the pilot poppet at a pilot poppet seat,wherein the valve is configured to operate in at least two modes ofoperation: (i) a counterbalance valve mode of operation in which thefirst fluid force and the second fluid force cooperate to overcome thebiasing force of the at least one setting spring, thereby unseating thepilot poppet and fluidly coupling the first port to the second port, and(ii) a proportional flow control mode of operation in which the solenoidactuator sleeve moves to the actuated state, thereby allowing the fourthport to be fluidly coupled to: (a) the first port to provide fluid flowto the first chamber of the actuator, and (b) the third port to providethe output pilot fluid signal to be communicated to the pilot port ofthe counterbalance valve to actuate the counterbalance valve and allowfluid to flow from the second chamber to the reservoir.
 15. Thehydraulic system of claim 14, wherein the valve further comprises: amain sleeve comprising the first port and the second port; and a housinghaving a cylindrical cavity in which the main sleeve is at leastpartially disposed, wherein the housing comprises the third port and thefourth port.
 16. The hydraulic system of claim 15, wherein the valvefurther comprises: a main flow piston configured to be have ametal-to-metal contact with the main sleeve to block fluid flow betweenthe fourth port and the first port when the valve operates in thecounterbalance valve mode of operation, wherein the main flow pistoncomprises the pilot poppet seat; and a main flow check spring configuredto bias the main flow piston toward the main sleeve, wherein when thevalve operates in the proportional flow control mode of operation, fluidflows from the fourth port through a longitudinal channel formed in themain sleeve and applies a respective fluid force on the main flow pistonagainst the main flow check spring, thereby separating the main flowpiston from the main sleeve, and opening a fluid path from the fourthport to the first port.
 17. The hydraulic system of claim 14, whereinthe valve further comprises: a solenoid coil, a pole piece, and anarmature that is mechanically coupled to the solenoid actuator sleeve,such that when the solenoid coil is energized, a solenoid force isapplied to the armature and the solenoid actuator sleeve coupledthereto, thereby (i) causing the armature and the solenoid actuatorsleeve to move axially in the proximal direction toward the pole piece,and (ii) placing in the solenoid actuator sleeve in the actuated state;and a main spring configured to bias the solenoid actuator sleeve to theunactuated state, wherein the solenoid force causes the solenoidactuator sleeve to move against a respective biasing force of the mainspring until the respective biasing force balances the solenoid force,wherein the fourth port comprises one or more inlet flow cross-holes,wherein the solenoid actuator sleeve is configured to (i) block the oneor more inlet flow cross-holes when the solenoid actuator sleeve is inthe unactuated state, and (ii) allow the one or more inlet flowcross-holes to be fluidly coupled to the first port when the solenoidactuator sleeve is in the actuated state.
 18. The hydraulic system ofclaim 14, wherein the third port of the valve comprises: (i) a firstpilot signal cross-hole configured to receive the input pilot fluidsignal when the valve operates in the counterbalance valve mode ofoperation, and (ii) a second pilot signal cross-hole configured toprovide the output pilot fluid signal to the pilot port of thecounterbalance valve when the valve operates in the proportional flowcontrol mode of operation, wherein the valve further comprises: a checkball configured to allow the output pilot fluid signal to becommunicated via the second pilot signal cross-hole when the valveoperates in the proportional flow control mode of operation, whileblocking the input pilot fluid signal at the second pilot signalcross-hole when the valve operates in the counterbalance valve mode ofoperation.
 19. A valve comprising: a plurality of ports comprising: (i)a first port configured to be fluidly coupled to a hydraulic actuator,(ii) a second port configured to be fluidly coupled to a reservoir,(iii) a third port configured to provide an output pilot fluid signaland receive an input pilot fluid signal, and (iv) a fourth portconfigured to be fluidly coupled to a source of fluid; a pilot poppetcomprising a distal poppet portion having a first diameter and aproximal poppet portion having a second diameter smaller than the firstdiameter; a solenoid actuator sleeve that is axially movable between anunactuated state and an actuated state; and at least one setting springconfigured to apply a biasing force on the pilot poppet in a distaldirection to seat the pilot poppet at a pilot poppet seat having a pilotpoppet seat diameter, wherein the pilot poppet is configured to besubjected to: (i) a first fluid force of fluid received at the firstport, wherein the first diameter, the second diameter, and pilot poppetseat diameter are configured such that the first fluid force issubstantially zero, and (ii) a second fluid force of the input pilotfluid signal acting on the pilot poppet in a proximal direction, andwherein the valve is configured to operate in at least two modes ofoperation: (i) a counterbalance valve mode of operation in which thesecond fluid force overcomes the biasing force of the at least onesetting spring, thereby unseating the pilot poppet and fluidly couplingthe first port to the second port, and (ii) a proportional flow controlmode of operation in which the solenoid actuator sleeve moves to theactuated state, thereby allowing the fourth port to be fluidly coupledto: (a) the first port to provide fluid flow thereto, and (b) the thirdport to provide the output pilot fluid signal to be communicatedexternally.
 20. The valve of claim 19, further comprising: a main sleevecomprising the first port and the second port; and a housing having acylindrical cavity in which the main sleeve is at least partiallydisposed, wherein the housing comprises the third port and the fourthport, wherein the pilot poppet comprises a flanged portion configured tointerface with an interior peripheral surface of the main sleeve toblock fluid flow from the fourth port to the second port when the valveoperates in the proportional flow control mode of operation.